全球关键干旱门 陆地碳汇-来源过渡
Wenwen Guo1, Shengzhi Huang1,2, Laibao Liu3
1State Key Laboratory of Eco-Hydraulics in Northwest Arid Region of China, Xi'an University of Technology, Xi'an, China.
Global change biology
|March 15, 2025
概括
干旱显著影响全球碳汇,可能导致碳吸收向释放的转变. 了解干旱值对于预测气候变化下的生态系统稳定性至关重要.
科学领域:
- 生态生态学 生态生态学
- 气候科学 气候科学
- 地球系统科学 地球系统科学
背景情况:
- 干旱是陆地生态系统中碳汇变化的主要驱动因素.
- 预计未来的气候变化将增加碳汇 - 源过渡的频率.
- 这些转变的干旱值的全球模式和机制尚未得到充分理解.
研究的目的:
- 绘制和分析全球干旱值的时空模式,以确定碳汇-源过渡的值.
- 确定影响这些干旱值的关键机制.
- 评估过去40年干旱值的动态变化.
主要方法:
- 利用了三个独立的数据集:植被动态模型,反向建模和观测数据.
- 在生长季节使用标准化降水蒸发转化指数 (SPEI) 绘制干旱值.
- 通过净生态系统生产率 (NEP) 标志的变化确定了沉源过渡.
主要成果:
- 在全球66.3%的土地上确定了干旱值,平均SPEI为-1.08 ± 0.68.
- 在北半球 (中高度) 发现了较低的值;在澳大利亚,非洲和美洲部分地区发现了较高的值.
- 潜在的蒸发转化是影响空间值模式的主导因素.
- 36.4%的门在研究期间增加,而55.8%的门在研究期间下降.
- 南美洲显示,由于对光合作用和呼吸的不成比例影响,值下降 (弹性增加).
- 北美呈现出越来越多的门值,这表明对干旱引起的沉源过渡的脆弱性更大.
- 发现二氧化碳施肥可以降低值并减轻气候变化影响.
结论:
- 这项研究提供了一个干旱值的全球地图,揭示了显著的区域差异.
- 了解干旱应对机制的区域差异对于预测未来碳循环动态至关重要.
- 干旱值越来越高的地区面临碳汇源转型的风险增加,气候变化下生态系统稳定性降低.
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